Effect of Tadalafil on Insulin Secretion and Insulin Sensitivity in Obese Men.

Obesity is a chronic disease of multifactorial etiology that develops from the interaction of the influence of nutritive , metabolic , cellular and molecular psychological factors. Tadalafil is Is a drug inhibiting the enzyme phosphodiesterase-5 (PDE-5), responsible for inactivating the vasodilator nitric oxide. USING paragraph was mainly treat erectile dysfunction, and recently approved for the treatment of pulmonary hypertension , it is innovative because of its longer life means, provides efficacy after 36 hours and the highest selectivity. The aim of this study is to evaluate the effect of tadalafil on insulin sensitivity and insulin secretion in obese men. The investigators hypothesis is that the administration of tadalafil improve the insulin sensitivity and insulin secretion in obese men.

A randomized, double-blind, placebo-controlled clinical trial in 18 men aged between 30 and 50 years with obesity (BMI 30-39.9) according to the World Health Organization (WHO) criteria without treatment. They will be assigned randomly in two groups of 9 patients, each to receive 5 mg of tadalafil or placebo every day at night during 28 days. There will be evaluated Insulin secretion, both first phase of insulin secretion by Stumvoll Inex as well as Total Insulin Secretion by Area Under the Curve of glucose and insulin and Insulinogenic Index, and Insulin sensitivity by Matsuda index. Waist circumference, glucose and insulin levels, lipid profile and blood pressure are going to be load will be evaluated before and after intervention in both groups. Statistical analysis will be presented through measures of central tendency and dispersion, average and deviation standard for quantitative variables; frequencies and percentages for variable qualitative. Qualitative variables will be analyzed by X2, will be used for differences inter-group Mann-Whitney U Test and Wilcoxon Test for the within-groups differences. Will be considered statistical significance p ≤0.05. This protocol was approved by a local Ethics Committee and written informed consent will be obtained from all volunteers.

Postprandial glucose will be evaluated at baseline and Day 28 after a oral glucose. tolerance test with enzymatic-colorimetric techniques.

First phase of insulin secretion will be calculated at baseline and Day 28 with Stumvoll Index. Human studies support the critical physiologic role of the first-phase of insulin secretion in the maintenance of postmeal glucose homeostasis. First phase of insulin secretion was estimated using the Stumvoll index (1283+ 1.829 x insulin 30' - 138.7 x glucose 30' + 3.772 x insulin 0'), the entered values reflect the first phase of insulin secretion

Total insulin secretion will be calculated at baseline and Day 28 with Insulinogenic Index. The insulinogenic index is a ratio that relates enhancement of circulating insulin to the magnitude of the corresponding glycemic stimulus. Total insulin secretion was calculated with the insulinogenic index (ΔAUC insulin/ΔAUC glucose), the entered values reflect the total insulin secretion

Insulin sensitivity will be calculated at baseline and Day 28 with Matsuda Index. Matsuda Index value is used to indicate insulin resistance on diabetes. Insulin sensitivity was calculated with Matsuda index [10,000 / √glucose 0' x insulin 0') (mean glucose oral glucose tolerance test (OGTT) x mean insulin OGTT)]. The entered values reflect the insulin sensitivity

Area under the curve of glucose measured at baseline and Day 28. The area under the curve (AUC) of glucose, (0.5 * glucose (G) 0´ + (G 30´+G 60´ + G 90´) + 0.5 * G 120´) * 30; has been widely used for calculating the glycemic index and for evaluating the efficacy of medications for postprandial hyperglycemia.

Area under the curve of insulin measured at baseline and Day 28. The Area Under the Curve (AUC) of insulin, (0.5 * Insulin (I) 0´ + (I 30´+I 60´ + I 90´) + 0.5 * I 120´) * 30; has been widely used for calculating the glycemic index and for evaluating the efficacy of medications for postprandial hyperinsulinemia.

Triglycerides levels will be evaluated at baseline and Day 28 with enzymatic-colorimetric techniques.

Total cholesterol levels will be evaluated at baseline and Day 28 with enzymatic-colorimetric techniques.

High density lipoprotein cholesterol (HDL-c) levels will be evaluated at baseline and Day 28 with enzymatic-colorimetric techniques.

Low density lipoprotein cholesterol (LDL-c) levels will be evaluated at baseline and Day 28 with Friedewald formula.

Inclusion Criteria: Men Age: 30-50 years BMI: 30 to 39.9 kg/m² No Pharmacotherapy during the last 3 months Signature Consent under Information Exclusion Criteria: Cholesterol: ≥ 240 mg / dl Triglycerides: ≥ 400 mg / dl Fasting glucose: ≥ 126 mg / dl Diabetes mellitus. Hypertension Patients with renal, liver and / or thyroid disease Consumption of drugs with known effects on glucose or insulin metabolism. Use of cigar and / or drugs Hypersensitivity to tadalafil